It is well known that there are three kinds of pillar on each side of a vehicle body called “A pillars”, “B pillars” and “C pillars”. The “A pillars” are inclined pillars on both side of the front windshield, the “B pillars” are pillars between the front and rear doors of the vehicle and the “C pillars” are inclined pillars on both side of the rear windshield. During traveling, a blind spot of a vision may be caused to the driver due to the “A pillars”, the “B pillars” and the “C pillars”, especially the “A pillars” (for example, the “A pillar” which is on the side closest to the driver may significantly infect the vision of the driver), which always results in inconvenience for driving or a traffic accident. The width of the “A pillar” is about 8 cm and assuming that the driver resides at the left of the vehicle, the angle of the blind spot caused by the left “A pillar” on the left vision for the driver is 6 degrees and the angle of the blind spot caused by the left “A pillar” on the right vision is 2 degrees. While a pedestrian or a vehicle happens to be within the blind spot on the left vision, the driver cannot see the pedestrian or the vehicle within the blind spot on the left vision, which results in occurrence of a traffic accident. Statistics shows that 20% of traffic accidents are related to “A pillars”.